Exception, Abstraction

What is the purpose of an abstract method?

• To define static behavior

• To hide all functionality

• To provide a method without implementation

• To override superclass method

What type of exception is NullPointerException?

• Checked

• Unchecked

• Compile-time

• Custom

Which keyword is used to manually throw an exception?

• throws

• throw

• exception

• raise

Which of the following is true about interfaces in Java?

• interfaces cannot have methods

• interfaces can have constructors

• interfaces can have static and default methods

• Interface methods are private by default

Which of the following is true about abstract classes in Java?

• An abstract class can be instantiated

• An abstract class cannot have any method

• An abstract class can have both abstract and non-abstract methods

• All methods in an abstract class must be abstract

Which of the following is not true about static methods?

• They can access only static variables directly

• They can call non-static methods directly

• They belong to the class, not objects

• They can be called without creating an object

Can an abstract method be private?

• Only if the class is final

• Only in interfaces

• yes

• no